[{"usage":{"maxNumberOfAddresses":{"seats":["193.34.136.242","138.61.33.44","96.160.197.255","151.34.143.231","255.90.212.146","182.57.86.6","102.171.187.32","150.157.38.224","207.156.239.153","59.194.105.191"]},"totalUsers":{"seats":["123","456","789",]}}},]

db.collection.aggregate([{$project:{usage:{$objectToArray:"$usage"}}},{$project:{usage:{$map:{input:"$usage",in:{k:"$$this.k",v:{toatl:{$size:"$$this.v.seats"}}}}}}},{$project:{usage:{$arrayToObject:"$usage"}}}])